On Wed, Apr 28, 2021 at 9:50 AM Wilco Dijkstra via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > > Use a GOT indirection for extern weak symbols instead of a literal - this is > the same as > PIC/PIE and mirrors LLVM behaviour. Ensure PIC/PIE use the same offset > limits for symbols > that don't use the GOT.
I thought that was changed not to use the GOT on purpose. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63874 That is if the symbol is not declared in the TU, then using the GOT is correct thing to do. Is the testcase gcc.target/aarch64/pr63874.c still working or is not testing the correct thing? Thanks, Andrew Pinski > > Passes bootstrap and regress. OK for commit? > > ChangeLog: > 2021-04-27 Wilco Dijkstra <wdijk...@arm.com> > > * config/aarch64/aarch64.c (aarch64_classify_symbol): Use GOT for > extern weak symbols. > Limit symbol offsets for non-GOT symbols with PIC/PIE. > > --- > > diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c > index > 82957dddbe42a7f907b2960294ac7f8abf7be2ff..08aaea70d952fd62147b7f06ba781eb55e697d3a > 100644 > --- a/gcc/config/aarch64/aarch64.c > +++ b/gcc/config/aarch64/aarch64.c > @@ -17854,7 +17854,12 @@ aarch64_classify_symbol (rtx x, HOST_WIDE_INT offset) > > switch (aarch64_cmodel) > { > + case AARCH64_CMODEL_TINY_PIC: > case AARCH64_CMODEL_TINY: > + if ((flag_pic || SYMBOL_REF_WEAK (x)) > + && !aarch64_symbol_binds_local_p (x)) > + return SYMBOL_TINY_GOT; > + > /* When we retrieve symbol + offset address, we have to make sure > the offset does not cause overflow of the final address. But > we have no way of knowing the address of symbol at compile time > @@ -17865,39 +17870,29 @@ aarch64_classify_symbol (rtx x, HOST_WIDE_INT > offset) > If offset_within_block_p is true we allow larger offsets. > Furthermore force to memory if the symbol is a weak reference to > something that doesn't resolve to a symbol in this module. */ > - > - if (SYMBOL_REF_WEAK (x) && !aarch64_symbol_binds_local_p (x)) > - return SYMBOL_FORCE_TO_MEM; > if (!(IN_RANGE (offset, -0x10000, 0x10000) > || offset_within_block_p (x, offset))) > return SYMBOL_FORCE_TO_MEM; > > return SYMBOL_TINY_ABSOLUTE; > > + > + case AARCH64_CMODEL_SMALL_SPIC: > + case AARCH64_CMODEL_SMALL_PIC: > case AARCH64_CMODEL_SMALL: > + if ((flag_pic || SYMBOL_REF_WEAK (x)) > + && !aarch64_symbol_binds_local_p (x)) > + return aarch64_cmodel == AARCH64_CMODEL_SMALL_SPIC > + ? SYMBOL_SMALL_GOT_28K : SYMBOL_SMALL_GOT_4G; > + > /* Same reasoning as the tiny code model, but the offset cap here is > 1MB, allowing +/-3.9GB for the offset to the symbol. */ > - > - if (SYMBOL_REF_WEAK (x) && !aarch64_symbol_binds_local_p (x)) > - return SYMBOL_FORCE_TO_MEM; > if (!(IN_RANGE (offset, -0x100000, 0x100000) > || offset_within_block_p (x, offset))) > return SYMBOL_FORCE_TO_MEM; > > return SYMBOL_SMALL_ABSOLUTE; > > - case AARCH64_CMODEL_TINY_PIC: > - if (!aarch64_symbol_binds_local_p (x)) > - return SYMBOL_TINY_GOT; > - return SYMBOL_TINY_ABSOLUTE; > - > - case AARCH64_CMODEL_SMALL_SPIC: > - case AARCH64_CMODEL_SMALL_PIC: > - if (!aarch64_symbol_binds_local_p (x)) > - return (aarch64_cmodel == AARCH64_CMODEL_SMALL_SPIC > - ? SYMBOL_SMALL_GOT_28K : SYMBOL_SMALL_GOT_4G); > - return SYMBOL_SMALL_ABSOLUTE; > - > case AARCH64_CMODEL_LARGE: > /* This is alright even in PIC code as the constant > pool reference is always PC relative and within
